The great extinction events are just icing on the cake. We get hit by rocks quite often, one of the most recent notable ones being the one that caused the Burck

The great extinction events are just icing on the cake. We get hit by rocks quite often, one of the most recent notable ones being the one that caused the Burckle Crater in the Indian ocean. The crater is 29km in diameter and the impact happened roughly 5000 years ago. The ocean impact would have created a mega-tsunami that devastated the coastlines of Australia, India, Africa, and South Asia. God knows what the fallout from it would have looked like but it would have vaporized a lot of water and also flung masses of ejecta into the atmosphere. Land impacts can be a lot worse since the damage isn't just limited to the impact site, that ejecta again creates a large radius of splash damage. Then there are the fires, the smoke, a nice dusting of radioactive material, and don't forget the shockwave and overpressure. We've been lucky so far but you'd have to be a fool to rely on luck forever.